1. Field of the Invention
The present invention relates to a video signal processing circuit for converting a color image into a monocolor image in which a specific color is adjusted to desired chroma, an imaging apparatus including the video signal processing circuit, a video signal processing method and a computer program product.
2. Description of the Related Art
There have been known several methods for changing a color image captured with an imaging apparatus such as a video camera into the image of a certain color tone. For example, monocolor processing has been typically used for video cameras as a method of representing an image as if the image was captured using a monotone film. Particularly, a function of changing a captured image into the image of a sepia tone as if the image was captured using a film is included in various imaging apparatuses.
Japanese Unexamined Patent Application Publication No. 2000-105820 discloses a method of generating a monotone image, for example. This method includes the steps of acquiring distribution of luminance equivalent values of respective pixels constituting an image, deriving a corresponding relationship in luminance conversion if any improvement is allowed in the luminance distribution, and generating a monotone image having luminance of the pixels converted based on the corresponding relationship.